Load transfer device



Patented May 15, 19451 UNITED STATESfPATENT OFFICE 2,552,831 LOAD TRANSFER DEVICE Ray Cyrus Yeoman, Lufkin, Tex.

Application March 16, 1945, Serial No. 583,032

` l e anims. (c1. :i4-'8) This invention relates to load transfer devices and more particularly to devices for transferring loads between adjacent slabs of concrete or the like. In laying concrete highways, runways and the like, it is customary to separate the concrete into slabs which are connected by expansible joints to make them weather tight and by dowels or the-like to transfer loads therebetween. The present invention has for one of its objects to provide a load transfer device for use with such slabs which issimple and inexpensive to manufacture and install and which will transfer both vertical and horizontal loads between adjacent slabs.

Another object is to provide a load transfer device formed of two members looped together at the joint between the slabs to transfer loads therebetween.

Still another object is to provide a load transfer device formed of rods or wires bent into a U shape and looped together. Preferably, the rods or wires are formed with flattened engaging surfaces to increase the bearing area therebetween.

The above and other objects and advantages of the invention will be more readily apparent from the following description when read in connection with the accompanying drawing, in which- Figure 1 is a vertical section through a slab joint illustrating a load transfer device embodying the invention;

Figure 2 is a section on the line 2-2 of Figure 1; and

Figure 3 is a view similar to Figure 1 illustrating an alternative construction.

As shown in Figures 1 and 2, a pair of adjacent concrete slabs I and Il are connected at a joint by a compressible filler strip I2. The strip I2 is formed with a series of openings therethrough through which load transfer devices may extend to connect the two slabs.

The load transfer devices of Figures 1 and 2 include pairs of identical members formed of rods or wire bent at the center to form U-shaped portions I3 from which legs I 4 extend outwardly to provide anchorage in the slabs. The U-shaped portions I4 extend beyond the slab faces into the joint space therebetween and are looped over each other, as shown. In installing the load transfer devices, the members are placed at right angles to each other and may lie in any desired position in the slabs, although one member of each pair is preferably arranged horizontally and the other vertically.

In order to increase the contact area between the devices the inner faces thereof throughout at least the U portions I3 are preferably flattened as shown at I5. Thus the flattened portions of each device will bear against similarly flattened portions of the other device to transfer horizontal loads and against the flat edge portions to transfer vertical loads.

In the case of a vertical load on one of the slabs tending to cause it to move relative to the other slab, the U-shaped portion I3 which lies in a horizontal plane will tend to move up or down and will engage one of the horizontal legs of the other U-shaped portion to limit vertical movement between the slabs. If the slabs should tend to separate due to contraction at low temperature, the looped portions of the load transfer members will engage each other to limit the permissible horizontal movement. It will be understood that the members may be so installed as to permit the desired amount of horizontal movement but to restrict the horizontal movement before the slab faces separate far enough to move out of contact with the filler I2. On expansion of the slabs, the members will move relative to each other to permit closing of the joint.

The looped portions of the load transfer members are preferably coated or covered with plastic material such as rubber, asphalt composition or the like as shown at I6. This material covers the exposed portions of the members to prevent rusting or corrosion thereof. It also yieldingly resists movement of the slabs toward and away from each other during expansion and. contraction and holds back the concrete before it has set to provide room for movement of each of the looped portions relative to the opposite slab. Preferably the coating is omitted from or is made thinner on the surfaces of the members which carry the vertical loads, as shown in Figure 1, so that minimum vertical movement of the slabs relative to each other is permitted.

Figure 3 illustrates an alternative construction, parts therein corresponding to like parts in Figures 1 and 2 being indicated by the same reference numerals. In this construction, the load transfer device is formed by a pair of members made up of rods or wire of square section bent into a U-shaped central portion I1 and outwardly extending legs I8 to be anchored in the slabs. The looped portions of these members or at least the vertical surfaces thereof are coated with plastic material I9. These members are installed in the same manner as the members of Figures 1 and 2 and operate in substantially the same way to transfer both vertical and horizontal loads between the slabs. The square section provides increased bearing area between the members, either directly or through the plastic material I9, for both vertical and horizontal load transfer but is otherwise substantially similar to the rod section of Figures 1 and 2.

While two embodiments of the invention have been shown and described in detail, it will be understood that these are illustrative only and are not intended as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. A load transfer device adapted to be i bedded in adjoining concrete slabs for transferring loads therebetween and for limiting separation thereof comprising a pair of substantially.

U-shaped members, each having its legs adjacent the U-portion substantially parallel and spaced apart to a distance substantially equal to the thickness of the U-portion and the legs diverging therebeyond, said U-shaped members being a1'- ranged in planes at substantially right angles and longitudinally looped over each other at the U- portions and adapted to have their legs .imbedded in the adjacent slabs with the looped U-portions between the slabs for transferring vertical loads between the adjacent slabs, and a covering of plastic material of substantial thickness on the U-portions of the members and providing limited long-itudinal movement between the members and adapted to provide limited separation of the adj acent slabs.

2. In combination with a pair of adjoining concrete slabs, a load transfer device imbedded in the adjoining slabs and comprising a pair of substantially U-shaped members, each having its legs adjacent the U-portion substantially parallel and spaced apart to a distance substantially equal to the thickness of the U-portion and the legs diverging therebeyond, said U-shaped members being arranged in planes at substantially right angles and longitudinally looped over each other at the U-portions and with their legs imbedded in the adjacent slabs and the looped portions between the slabs for transferring vertical loads between the adjacent slabs, and a covering of Y plastic material of substantial thickness on the U-portions of the members and providing limited longitudinal movement between the members and limited separation of the slabs.

RAY CYRUS YEOMAN.

REFERENCES CITED V The `following references are of record in the file of this patent:`

UNITED STATES PATENT 

